Engine castings and their parts can crack due to stress, age and overheating and are not always visible to the naked eye.
Here at Ridge Engine Machine & Repair we use 3 types of crack detection.
The most popular type is magnafluxing, castings are cleaned from oil, dirt and gasket material and are placed under an electrical current which magnetizes the casting. A powdered solution is then placed on the part and will adhere to the crack making it visible. Magnafluxing is used only will iron castings and parts.
Another type of crack detection is Pressure checking. Pressure checking can be used on both iron castings and aluminum and it is the best type of crack detection, because it checks cooling systems, oil galley’s and injector cups in diesel head castings. Castings are placed in a cradle and metal plates cover the deck of the head and open champers to the cooling system, then pressurized to double the normal cooling system pressure. The castings are then lower into a tank of water and checked for air bubbles coming from the casting, oil galley’s or injector cups.
The last is the Dye Penetrant type, which is a three stage process. It can be used on both iron and aluminum castings. Castings are cleaned and sprayed with the first penetrant and dried allowing the penetrant into the cracks of the casting. The second stage is removing the excess penetrant with remover and the last stage is to spray developer on the casting which draws out the first penetrant and shows the cracks in the casting.